Measuring device



CARL Jl. FECHHEIMER, OFV PITTSBAUKRGH, PENNSYLVANA, ASSIGNOR TOES'IIINGr-i` HOUSE ELECTRIC -& MANUFACTURING COMPANY, A`COIEtPOIEtA'JIION 0Fl PENNSYL- Patented Dec. 1, 1931 UNITED Ausw-TATESVANIA PATENT crie-ici;A

iiiiiiisrmairerl :DEVICE Application led Septembery 8, 1925i rSerial No.54,886.

My invention relates to measuring devices and particularly to devicesfor measuring static pressures in spaces containing flowing fluids.

One object of my invention is to provide a,

device of the above-indicatedV character that shall be simple anddurable in construction and effective in its operation. f r

Another object of my invention is to provide a device that shall sonullify the eect of a flowing fluid as to obtain a very accuratemeasurement of the static pressure in a space containing the flowingfluid.

, In static pressure measuring devices asl heretofore suggested, variouserrors in the reading of static pressure have been introduced, thevelocity head or a fraction thereof being added to or subtracted fromthe static pressure, and, to the best of my knowledge,

no device of this character has operated to a satisfactory degree ofaccuracy. Y

In bulletin No. 394, issued by the Bureau of Standards and entitled Airforces on circular cylinders, it is shown that the angle between thedirectionof the wind and the position on the cylinders surface where thevelocity heads influence is negligible, is quite clearly defined and isabout Accordingly, in practicing my invention, I utilize theabove-disclosed phenomenon by providing a device embodying a cylindricalmember having two openings disposed approximately 40 on opposite sidesof a point ,8. on the surface of the cylinder, a line between vaccordance with my invention,

Fig. 2 is a view partially in section taken aiong the une ii-ii of Fig.i and partially in elevation of the device including the manometer andits connections, and

Fig. 3 is a view taken along the line III-III of Fig. 2.

Iny its simplest and preferred form,"theude vice'comprises in general, apressure-chamber` structure 1, a U-tube or manometer 2 and means 3 and 4such as flexible rubber tubing i 'i for connecting thepressurefchambei'. structure 1 tothe manometer 2. f

` The pressure chamber structurel 'come prises concentrically disposedtubes. 6 and 7 that 'are each closed at one end as by discoidaly endportions 8. A space 9 between the members 6 and 7 is closed, as byanannularmember or ring 10, at the other 'vend of thegmember 6 vwhichmay bean integral depressed or lcrimpedportion of the member 6, vas.shown.

*The tubular member 3 connects oneleg-of th'e'ma'nometer 2 to the space9 between the tubes'and 7 in the structure 1, through. a valvell and atubular projection 12 on the outer member V6, and the tubular member. 4

connects the other leg of the manometer to the interiorof the inner tube7 of the structure l,

lThe outer tubular member 6. is provided at an intermediate positionthereon with an Vopening v14 which provides communication between `thespace 9 and the exterior ofthe structure 1. A relatively small tubularmem-L ber 15 is sealed between diametrically opposite openings-in themembers 6 and .7 to proy vide 'an opening 16 from the exterior of thestructure 1 tothe interior ofthe member 7,

that is angula'rly or circumferentially related totheopening 14 at apredetermined 'distance therefrom, this distance, as hereinbe-vforenmentioned,v is approximately 80, or twicethe distance of one of theopenings from the longitudinal axis `of the wind 'stream at which thevelocity heads influence is negligible. I have'found '781/2o to beaneffective working'distance between these openings.

In' operation, the structure 1` isplaced a duct or other spacecontaining a flowing fluid. as represented by arrows 17 in Fig. 3, andturned about its longitudinal axis until a point midway betweentheopenings 14 and 16 is disposed on the longitudinalaxis of the flowingstream, represented by the central arrow 17 or, in other words, untilthe levels of a liquid body 18 in the manometer 2 are jbalanced. Thiscondition indicates that the effeet of the kinetic pressure lof theflowing fluid has been nullified by the angular arrangement of thedifferentially opposed openings 14 and 16 and their relation to theiiowing liuid. After this adjustment has been made, one of the legs ofthe manometer 2 may be opened to the atmosphere as by removing one endof one of the flexible tubes 3 or 4L, or by manipulating the valve l1.Opening of one of the legs of the manometer 2 to the atmosphere causesthe liquid in the manometer to assume new levels in accord-v ance withthe static pressure in the duct or Vspace in which the structure l isdisposed.V

It will be appare-nt to those skilled in the art that a sphere may beused in lieu of the cylinder G and that two manometer tubes may besubstituted for one manometer tube and the valve, without departing fromthe spirit and scope of my invention, as set forth in the appendedclaims.

I claim as my invention 1. .A device for measuring the static pressurehead in a moving fluid comprising two concentric cylinders providing achamber therebetween and the outer cylinder having two small openingstherethrough spaced circumferentiallv by an angle substantially edual to'double the angle from the directiony of .stream flow to that positionon said surface at which the inliuence of the velocity head isnegligible, means provi-ding a passageway between the chamberconstituted by the space within the inner cylinder and one of saidopenings. amanometer, and means for connecting the two chambers to theterminals of the manometer, the manometer being adapt.- ed to bebalanced by rotation of the cylinders about the axis of svmmetrvthereof, one side of the manometer being' adapted for communication withthe atmosphere to measure the static pressure after the manometer hasbeen balanced.

2. A device for measuring the static pressure head in a moving fluidcomprising a cylindrical structure providing .chambers cornmunicating,respectively, with small openings inthe outer surface of the: structureand spaced circumferentiallv about the cylinder bv an anglesubstantially equally to 'double the angle'from the direction of streamiiow to that position on said surface at which the influence of thevelocity head is negligible, and means in communication with thechambers responsive to differential pressures therein, said `pressuresto be adjusted until thev are substantially equal bv rotation of saidstructure about its longitudinal a-Xis and the static pressure to benieasured'bv relieving thepressure at one side of saiddifferentialpressure-responsive means.

3.y A device comprising a structure having an .outer surface of circularcross-sectional contour about an axis for position at subrelativelysmall outer-surface 'openings cir-t CARL J. FE CHHEIMER.

